In the above-noted related applications, completely flexible bronchoscopic needle assemblies are disclosed wherein relatively non-invasive biopsy procedures can be performed utilizing the needles in combination with a fiberoptic bronchoscope. The attending physician inserts the bronchoscope into a predetermined one of the patient's natural orifices depending upon the particular organ desired to be biopsied. Thereafter, a needle assembly in accordance with the invention described in the above-noted related applications is slideably inserted into a receiving passageway of the bronchscope. The needle is urged into the tissue of the patient by a stabbing force exerted on the proximal end thereof (i.e. the end on the exterior of the patient's body) after the tubular needle portion comes into the bronchoscope's field of view. The bronchoscope enables the attending physician to accurately position the needle and to penetrate the exact location of the desired organ due to the viewing capabilities provided thereby. The present invention is directed to improvements in the needle assemblies of the types generally disclosed in my related applications referenced above.
Heretofore, when biopsies were desired to be taken of the lymph nodes, for example, so as to aid in the diagnosis of carcinoma, the prior techniques would all typically utilize a substantially rigid needle and penetrate the body via percutaneous entry. For example, U.S. Pat. Nos. 3,630,192 and 3,628,524 each to Jamshidi disclose prior art biopsy needles suitable for percutaneous entry. It has been proposed via U.S. Pat. No. 4,249,541 to Pratt that a flexible biopsy instrument can be utilized in combination with a fiberoptic bronchoscope. One problem with Pratt's needle device, however, is that no protective structures are provided when the needle assembly is inserted through the fiberoptic bronchoscope so as to protect, not only the fiberoptic bronchoscope but also the patient from inadvertant damage due to the sharp edge of the needle until such time as the physician desires to penetrate the patient's internal organ tissue.
In order to provide accurate biopsies, a sufficient quantity of biopsy tissue material must be obtained so that adequate testing can be performed. In order to obtain a greater quantity of tissue samples, it is of course conceivable to utilize a biopsy needle having a relatively large lumen. However, the use of large-lumen biopsy needles is disadvantageous since a fairly large puncture wound will be necessary if a biopsy is to be taken, for example, of tissue behind the bronchial walls of a patient such that excessive bleeding may result when the needle is withdrawn.
The present invention overcomes such problems by providing a flexible bronchoscopic needle having an elongated flexible catheter to which a rigid hollow sampling needle is coaxially fixed at the distal end thereof. An increased quantity of tissue sample can be obtained in accordance with the present invention by the provision of a lateral opening in the sampling needle. The lateral opening is defined by a rearward lateral cutting edge which functions so as to cut into the tissue when the sampling needle is forcibly advanced and a gradual inwardly slopped surface defined forwardly of the lateral cutting edge which functions so as to prevent the tissue from being cut when the sampling needle is withdrawn. The distal end of the sampling needle also includes a bevelled forward cutting edge which is disposed in a plane substantially transverse to the sampling needle. Accordingly, tissue cutting functions are provided not only by the forward bevelled cutting edge but also by the lateral cutting edge of the lateral opening. Moreover, such cutting functions are effective only when the sampling needle is advanced into tissue such that upon repetitive advancement and withdrawal of the sampling needle, the cut tissue will be forcibly accumulated in the hollow of the sampling needle. In such a manner, the structures of the present invention permit an increased quantity of tissue samples to be obtained.
A further aspect of the invention relates to the means by which the lateral cutting edge is effectively masked so as to prevent it from cutting into tissue. According to the present invention therefore there is also provided an inner needle which is slideably reciprocally receivable within the hollow of the sampling needle and is moveable between an advanced position wherein the inner needle adjacently blocks the lateral opening and a retracted position wherein the inner needle is rearwardly withdrawn from the lateral opening to permit passage of tissue therethrough. Preferably, the inner needle at its distal end defines a sharp surface which projects outwardly from the forward cutting edge of the sampling needle when the inner needle is in its advanced position.
The sharp surface of the inner needle thus initially penetrates the bronchial walls of a patient, for example, so as to provide a small-sized pilot incision of sorts. The larger-sized sampling needle will thus be forced through the pilot incision without further cutting action by virtue of the masked relationship of the forward cutting edge. Similarly, the inner needle will mask the lateral cutting edge so that no cutting functions of the bronchial wall other than the small pilot incision will be initially effected while yet permitting the sampling needle to be extended through the bronchial wall and into the tissue therebeyond. Upon retraction of the inner needle, the forward cutting edge and the lateral cutting edge of the sampling needle are thus effectively unmasked thereby permitting their cutting functions to be performed upon forcible advancement of the sampling needle into the tissue to be biopsied.
As such, the structures of the present invention prevent large-sized incisions in a patient's bronchial walls, for example, while yet permitting a larger quantity of sample tissue to be obtained. The above advantages of the present invention, as well as others, will become more clear to the reader after careful consideration is given to the detailed description of the preferred exemplary embodiments thereof which follows.